EP1554513B2 - Stop valve - Google Patents

Abstract

The invention relates to a stop wedge for a stop valve, which is designed to be moved in translation along a displacement axis (T-T). The wedge consists of a sealing panel comprising a distal end (60) which is intended to be applied against a sealing seat (22) and two lateral guide elements (82, 84). The stop wedge (6) also comprises a stopping surface (A) which comes into contact with the pressurised liquid and which is projected onto the displacement plane (C-C) when the stop wedge (6) is in the closed position. The distal ends (98, 100) of the aforementioned guide elements (82, 84) are separated from the distal end (60) of the stop wedge (6) by a distance dp which is measured along the displacement axis (T-T). The stopping surface (A) has a height H along the displacement axis (T-T), while the dp/H ratio is less than 0.34.

Description

The present invention relates to a stopping wedge for a stopping valve, according to the preamble of claim 1.

Such a stopping corner is known to DE2843163 .

The document GB-A-724,577 describes another stopping corner.

It applies in particular to sectioning valves.

A shutoff valve is known from the document EP-A-0 926 410 .

This valve comprises a housing and a wedge. The stop wedge has two lateral guide pads cooperating with longitudinal grooves in the housing, between an open position and a closed position. The guide pads are located at the equibarycentre of the shutter surface projected on the plane of displacement of the stopping corner. This arrangement leads to a balance of the stopping corner under the force applied by the liquid when the valve is in the closed position, that is to say in the static case.

However, when moving between its open and closed positions, the stopping corner of this valve is subject to a tilting torque. The tilting torque is generated by the pressure and velocity field created by the flow of fluid that meets the operculum. This tilting torque has the effect of moving the stop wedge out of the plane perpendicular to the direction of movement of the liquid. As a result, a sealing lip carried by the stopping corner is offset from the sealing surfaces of the housing, which affects the sealing of the valve in the closed state.

The present invention aims to overcome the disadvantage cited, and to provide a stop valve which ensures a good seal.

Another object of the invention is to indicate a stop valve which has a long service life of the guide elements.

For this purpose the invention relates to a wedge of the aforementioned type, characterized by the characteristics of the characterizing part of claim 1.

According to other embodiments of the stopping wedge, this includes the features of the dependent claims 2 to 11.

The invention further relates to a shut-off valve having the features of claim 12.

• la Figure 1 est une vue de côté du boîtier d'une vanne d'arrêt selon l'invention ;
• la Figure 2 est une vue en coupe de la vanne selon la ligne II-II de la Figure 1, le coin d'arrêt étant dans sa position ouverte ;
• la Figure 3 est une vue analogue à la vue de la Figure 2, le coin d'arrêt étant dans sa position fermée ;
• la Figure 4 est une vue schématique de plan d'un coin d'arrêt selon l'invention ; et
• les Figure 5 et 6 sont des vues en coupe du coin d'arrêt selon les lignes V-V et VI-VI de la Figure 4.

The invention will be better understood on reading the description which follows, given solely by way of example and with reference to the appended drawings, in which:

• the Figure 1 is a side view of the housing of a stop valve according to the invention;
• the Figure 2 is a sectional view of the valve along line II-II of the Figure 1 the stopping corner being in its open position;
• the Figure 3 is a view similar to the view of the Figure 2 the stopping corner being in its closed position;
• the Figure 4 is a schematic plan view of a stopping wedge according to the invention; and
• the Figure 5 and 6 are sectional views of the stopping corner along lines VV and VI-VI of the Figure 4 .

On the Figures 1 and 2 is represented a stop valve according to the invention, designated by the general reference 2.

This stop valve 2 is intended to be inserted into a liquid supply line (not shown), for example water, in order to stop the flow of liquid if necessary.

The shut-off valve 2 comprises a valve housing 4 and a shutter 6 movable in translation designated in the following by stopping corner.

The valve housing 4 is made integral with the supply line in a liquid, flowing in a direction of flow L , by means of an inlet connection 8 and an outlet connection 10. Both connectors 8, 10 are arranged coaxially with respect to a central axis XX of liquid flow, and define a section circular flow S ( Figure 2 ) Of diameter d _e. In the mounted state of the stop valve 2, the axis XX extends horizontally.

The valve housing 4 further comprises a housing 12 for the stopping wedge 6, disposed between the two connectors 8, 10. The housing 12 comprises, in its upper part, an opening 14 for introducing and operating the corner In the following, the expression "proximal" will designate a location close to this opening 14, while the expression "distal" will be used for locations that are offset or remote from this opening 14 in the direction directed towards the XX axis.

The stop wedge 6 is disposed in the housing 12 so as to be slidable between an open position, in which the liquid can pass unobstructed from the inlet fitting 8 to the outlet fitting 10, and a closed position, shown in FIG. Figure 3 , in which the liquid is retained in the inlet connection 8. The stop wedge 6 can slide in translation in a vertical direction of displacement D in a plane of displacement CC, which plane extends perpendicular to the direction XX d flow of the liquid.

The valve 2 further comprises drive means 16 of the stopping wedge 6 between its two open and closed positions. These drive means 16 comprise a threaded rod 18 extending radially to the axis X-X in the plane C-C along a vertical axis T-T. In what follows, the terms "median" and "lateral" will be used with respect to this T-T axis.

The rod 18 has a proximal operating end protruding from the housing 4 and a distal end extending in the vicinity of the flow section S without overlapping it. The rod 18 is rotatable but axially fixed relative to the housing 4 and connected to external rotary drive means (not shown).

The driving means 16 of the stopping corner 6 further comprise a block 19 of T profile, fixed at the stop wedge 6, in which block is formed a tapping inside which is screwed the threaded rod 18.

Moreover, as represented Figures 3 and 4 two retaining brackets 20A, 20B protrude from the proximal end of the wedge, parallel to the axis TT and being bent thereto. They form a receptacle 21 complementary to the threaded block 19 for receiving it.

The housing 12 of the housing defines a sealing seat 22 of the stopping wedge 6. This sealing seat 22 comprises a medial distal support surface 24, two lateral distal support surfaces 26, 28, and two proximal lateral supports 30, 32, one of which is visible on the Figure 2 .

The medial distal support surface 24 is located vis-à-vis the distal end of the threaded rod 18. It has a partial cylinder shape of axis XX; whose diameter is identical to the diameter d _e of the flow section S of the connections 8, 10. View along the axis TT, it has a circular shape of diameter d _t slightly greater than the diameter of the threaded rod 18. Each of the two lateral distal bearing surfaces 26, 28 are connected tangentially to the medial distal support surface 24 in the plane CC, on either side of the axis TT. The two lateral distal bearing surfaces 26, 28 are rectilinear along their entire length. They form an angle α with a plane PP extending perpendicularly to the axis TT. This angle α is less than 30 °, especially less than 20 ° and preferably less than 10 °. Due to this low inclination, the pressure exerted on the part of the sealing lip of the wedge 6 corresponding to the surfaces 24, 26, 28 is important for a given application force. In addition, the sealing lip is subjected to low shear forces.

In addition, the inclination is greater than 0 °, soils, which are eventually provided by the liquid, are prevented from being deposited. The sealing seat 22 is self-cleaning.

Viewed along the X-X axis the distal portion of the seal seat 22 is substantially in the shape of a round-headed arrow.

The two proximal bearing surfaces 30, 32 extend on either side of the plane CC and have a general shape of horseshoe. They are inclined with respect to the plane CC by an angle β (see Figure 1 ). The angle β can be between 10 ° and 35 °. Each of the two proximal bearing surfaces 30, 32 surrounds the flow section S on the proximal side. As illustrated on the Figure 1 the distal ends of the two proximal bearing surfaces 30, 32 are connected to the lateral proximal ends of the lateral distal bearing surfaces 26, 28 by two shoulders 34, 36.

Furthermore, the stop valve 2 comprises means 38 for guiding the stop wedge 6 in the housing 12.

The guide means 38 comprise guide grooves 40, 42, which extend substantially in the plane CC and parallel to the axis TT, and this from the lateral proximal ends of the lateral distal support surfaces 26, 28, towards the opening 14 of the housing.

The stop wedge 6 comprises a closure panel which consists essentially of a core 44 of rigid material, for example cast iron, and a coating 48 of elastic plastic material, for example rubber or elastomer.

The coating 48 surrounds the core 44 completely and provides corrosion protection thereof.

The stopping wedge 6 comprises a web 52 which delimits a stopping surface A. The stopping surface A is defined as the free surface of the stopping wedge 6 which comes into contact with liquid under pressure, when the wedge stop is in its closed position, projected on the DC movement plane. The equibarycenter of this stopping surface is named G. In its closed position, the stopping wedge 6 stops the liquid on the stopping surface A. In the present example, the equibarycentre G is close to the axis XX when the stopping corner 6 is in its closed position. The stop surface A has a height H measured along the axis of displacement TT.

The web 52 consists of a hollow cylindrical central tube 54 and two wings 56, 58.

The central tube 54 is arranged, in the mounted state, coaxially with the axis TT of the threaded rod 18. The internal diameter d _i of the central tube 54 is greater than the external diameter of the threaded rod 18 so that the tube 54 can receive the rod 18. The outer diameter of the central tube 54 corresponds to the diameter d _t of the medial distal support surface 24 seen along the axis TT. The distal end 60 of the central tube 54, seen along the axis XX, has an arcuate profile of diameter d _e .

The two wings 56, 58 are solid wall portions which extend on either side of the T-T axis along the plane of displacement C-C. The distal portion of each wing 56, 58 comprises a rectilinear edge 62, 64 which, in side view, connects tangentially to the arc of the distal end 60 of the central tube 54. The edges 62, 64 have a shape complementary to the lateral distal bearing surfaces 26, 28 of the housing 4. Each edge 62, 64 is inclined at the angle α with respect to the plane PP. In addition, the two straight edges 62, 64 extend, from the arc of the circle, over the entire width of the web 52, measured in the plane of displacement C-C perpendicular to the axis of displacement T-T.

As represented in Figures 4 and 5 , the wedge 6 further comprises two sealing ribs 66, 68 shaped horseshoe, complementary to the proximal bearing surfaces 30, 32 of the housing 4. The sealing ribs 66, 68 protrude from the surface of the web 52 perpendicular to the plane of displacement CC, on either side of this plane. The proximal portion 70 of the sealing ribs 66, 68 is in the form of a hollow half-cylinder. It is extended at each distal end by a rib portion 72, 74 rectilinear extending to the lateral end of the edge 62, 64 of each of the wings 56, 58. At this location the rib 66, 68 form a truncated tip 76, shown in dashed line on the Figure 6 , corresponding to the shoulders 34, 36 of the housing.

As is apparent from the Figure 6 each rib 66, 68 is delimited by a plane HH which is inclined at the angle β on the plane CC, and which intersects this plane beyond the distal end 60 of the central tube 54. The height of each rib 66 , 68 measured with respect to the plane CC therefore decreases from its proximal end to its distal end.

The edge of each rib 66, 68, the distal end 60 of the central tube 54, and the distal edge 62, 64 of each wing 56, 58 consist of a bead of the coating 48 forming the sealing lip 80. This lip 80 is of complementary shape to the surface of the sealing seat 22 of the housing 12 of the housing 4.

The stop wedge 6 further comprises two guide tips 82, 84 forming part of the guide means 38 of the stopping wedge 6. These tips are able to slide in the grooves 40, 42. Each guide tip 82, 84 is formed by a lateral projection of the coated core 44, covered by a sliding shoe 88, 90 for example rigid plastic with high resistance to abrasion, such as polyamide. The sliding pads 88, 90 are fixed by overmolding the material of the coating 48 on the projections of the core 44.

The guide tips 82, 84 extend in the direction of movement D. Each of the tips 82, 84 has a proximal end 94, 96 and a distal end 98, 100. The distal end 98, 100 of each guide tip 82, 84 is disposed at a distance d _p from the distal end 60 of the central tube 54, measured along the axis of displacement TT.

When moving the stopping wedge 6 to its closed position, the liquid exerts a dynamic force F _dyn on the stopping wedge, which is directed in the liquid flow direction L.

The distal ends 98, 100 of the guide tips 82, 84 are arranged in such a way that the point of application of the resultant of this dynamic force F _dyn , at least immediately before the total closure, is located on the proximal side of the distal ends. 98, 100.

entre les grandeurs d _p et H est choisi inférieur à 0,34, notamment inférieur à 0,3 et de préférence inférieur à 0,25.The report $\frac{{\underset{}{d}}_p}{\underset{}{H}}$

between the quantities of _p and H is chosen less than 0.34, especially less than 0.3 and preferably less than 0.25.

The smaller this ratio, the greater the tilt torque exerted by F _dyn is large at the time of closure of the valve.

The shut-off valve is assembled as follows.

The casing 4 and the core 44 of the wedge 6 are made of cast iron. The elastomer coating 48 is overmolded on the core 44. Then the sliding pads 88, 90 are plugged onto the projections of the core 44 of the wedge 6 and fixed on the projections. Then, the threaded block 19 is inserted between the retaining brackets 20A, 20B and the threaded rod 18 is screwed into the tapping. The stopping wedge 6 and the threaded rod 18 are inserted into the housing 4 through the opening 14. Finally, the rod 18 is connected to the housing 4 and to the rotating drive means.

During operation, when the stopping wedge 6 is in its open position, the liquid can freely pass through the housing 4. When the liquid flow has to be stopped, for example in the case of a rupture of the pipe located downstream of the valve 2, the threaded rod 18 is rotated, so that the stopping wedge 6 moves to its closed position, in the direction D.

From the moment when the stopping wedge 6 overlaps the flow section S, the liquid exerts on the stopping wedge 6 the dynamic force F _dyn of tilting directed in the downstream direction. This force forces in a first step, the stopping wedge 6 in the direction of a tilting out of the plane of displacement CC, around the tapped block 20. During the continuation of the displacement, the point of application of the resultant of the dynamic force F _dyn moves from the distal end 60 towards the middle of the stopping corner 6. When the point of application of the resultant of the dynamic force F _dyn crosses the level of the distal ends 98, 100 of the guide ends 82 , 84, the stopping corner 6 tilts around an axis BB. This axis BB is defined by the portions of the guide tips 82, 84 applied to the guide grooves 40, 42. From this moment, the guide tips 82, 84 are applied at full height to the guide grooves. .

As a result, the stopping wedge 6 extends parallel to the plane C-C, so that the application of the distal end of the stopping wedge 6 is carried out perpendicular to the sealing surface. Thus, the shutoff valve ensures a good seal.

Due to the fact that the distal ends 98, 100 of the guide tips 82, 84 are at a short distance from the distal end 60 of the central tube 54, and therefore the distal end of the stopping wedge 6, measured in the direction D, the stopping corner is kept close to its distal end, at a great distance from the tilting axis. Thus, for a given pressure of the liquid, the force applied on the lower end of the pads is low. As a result, the offset of the sealing lip 80 with respect to the sealing seat 22 is small, which leads to a good sealing of the stop valve 2 for a given bearing force of the stopping wedge 6 against the seat 22.

Moreover, the force applied to the sliding shoes 88, 90 is low, which leads to a low wear thereof.

In addition, since the offset of the corner stopping out of the DC plane is limited, the actuating forces of the threaded rod 18 are small. The drive means for rotating the rod (geared motor) can have a low nominal force and be economical.

Alternatively, the stopping corner includes lateral guide grooves instead of the guide ends. In this case, the valve housing comprises corresponding guide tips and the grooves of the stop wedge cooperate with these tips.

Claims (12)

1. Closure wedge for a shutoff valve, designed to be displaced in translation along a displacement axis (T-T) which is disposed in a displacement plane (C-C) in a valve casing (4) and which extends transversely to the flow direction (X-X) of a liquid, of the type comprising:

   - a shutter panel having a proximal end comprising means (20A, 20B) for establishing a connection to means (16) for driving the closure wedge (6) and a distal end (60) designed to be applied against a seal seat (22) of the valve casing (4);

   - two lateral guide members (82, 84) designed to co-operate with complementary guide members (40, 42) of the valve casing (4) with a view to displacing the closure wedge (6) between open and closed positions of the shutoff valve (2) ;

   the closure wedge having a stop surface (A) which is defined as the free surface of the closure wedge (6) which comes into contact with the pressurised liquid projected onto the displacement plane (C-C) when the closure wedge (6) is in its closed position, the distal ends (98, 100) of the lateral guide members (82, 84) being spaced apart from the distal end (60) of the closure wedge (6) by a distance d _p measured along the displacement axis (T-T), the stop surface (A) having a height H measured along the displacement axis (T-T), the closure wedge comprising a screen (52), as viewed in the flow direction of the liquid (X-X), the distal end (60) of the screen (52) having a contour that is substantially a circle arc in the region of the displacement axis (T-T) and two straight edges (62, 64) joined to this arc at a tangent on each side of the displacement axis (T-T), characterised in that the ratio $\frac{{\underline{d}}_p}{\underline{H}}$

   

   is less than 0.34,
   and in that the angle (α) subtended by a plane (P-P) extending perpendicular to the displacement axis (T-T) and each of the straight edges (62, 64) is less than 30°, in particular less than 20°, and preferably less than 10°.
2. Closure wedge as claimed in claim 1, characterised
   in that the ratio $\frac{{\underline{d}}_p}{\underline{H}}$

   

   is less than 0.3 and preferably less than 0.25.
3. Closure wedge as claimed in any one of claims 1 or 2, characterised in that the two straight edges (62, 64) extend from the circle arc across the entire width of the screen (52), measured in the displacement plane (C-C) perpendicular to the displacement axis (T-T).
4. Closure wedge as claimed in any one of claims 1 to 3, characterised in that the angle (α) is greater than 0°.
5. Closure wedge as claimed in any one of claims 1 to 4, characterised in that the screen (52) comprises a central tube (54) extending coaxially with the displacement axis (T-T) and two lateral flanges (56, 58) extending on either side of the central tube (54) along the displacement plane (C-C), the distal end (60) of the screen (52) being formed by an end of the central tube (54) in the region of the displacement axis (T-T).
6. Closure wedge as claimed in any one of claims 1 to 5, characterised in that the lateral guide members comprise lateral guide pieces (82, 84) designed to co-operate with guide grooves (40, 42) of the valve casing.
7. Closure wedge as claimed in any one of the preceding claims, characterised in that the lateral guide pieces (82, 84) are covered by slide shoes (88, 90) made from rigid plastic material, in particular polyamide.
8. Closure wedge as claimed in claim 7, characterised in that the slide shoes (88, 90) are connected to the core (44) by moulding onto the plastic material of the facing (48).
9. Closure wedge as claimed in any one of claims 1 to 5, characterised in that the lateral guide members comprise guide grooves provided in the closure wedge.
10. Closure wedge as claimed in any one of the preceding claims, characterised in that the shutter panel comprises:

    - a core (44), in particular of cast iron; and

    - a facing (48) of elastic plastic material forming a sealing lip (80).
11. Closure wedge as claimed in claim 10, characterised in that the facing (48) completely surrounds the core (44) .
12. Shutoff valve comprising a shutoff valve casing and a closure wedge, the valve casing (4) comprising a housing (12) for the closure wedge (6), which housing bounds a seal seat (22) and which has an opening (14) for inserting the closure wedge (6), the seal seat (22) having a distal support surface (24, 26, 28) disposed facing the insertion opening (14), this support surface (24, 26, 28) comprising a median distal support surface (24) with a partial cylindrical contour and two straight, lateral distal support surfaces (26, 28) which are joined to the median distal support surface (24) at a tangent, characterised in that the closure wedge is as claimed in any one of the preceding claims.

Images